/* CSS banner */
.banner{width:100%; border-top:1px #656563 solid; overflow: hidden;}
.banner_middle{width:1200px; margin:0 auto; height:321px; position:relative;}
.banner_middle_box{height:321px;}
.banner_middle_box1 img,.banner_middle_box2 img{float:left; height: 321px;}
.banner_middle_box1{width:300%; position:absolute; left:-1200px;}
.banner_middle_box2{width:300%; position:absolute; left:2400px;}
.btn_left,.btn_right{top:0px; background:#000;  filter:alpha(opacity=40); -moz-opacity:0.4; -khtml-opacity:0.4; opacity:0.4; height:321px; cursor:pointer;}
.btn_left{right:1200px;}
.btn_right{left:1200px;}
.ab { position:absolute; }
